1. Field
One or more embodiments relate to technology for detecting a facial area in an image.
2. Description of the Related Art
Demand has been increasing for an automation device for detecting a face of a person and finding presence, location, and direction of the person to recognize an identity of the person and provide services specific to people.
Examples of such an automation device include a secure system that recognizes a face of a visitor to a secure entrance, a notebook computer with a camera that senses a face of a user for log-in, and a camera that detects a face to capture a smile.
In a face detection technique that has been most widely used recently, a sub-window having several sizes is moved over all areas of an image and portions of the image, detected through the sub-window, are classified as either representing a facial area or a non-facial area.
In this case, classification of the facial area and the non-facial area is performed by a serial classification unit that includes several continuously connected classifiers. That is, when a face is detected in a portion of the image by the classifier in each operation, a process proceeds to a next operation, while when a background is detected in the portion of the image, the process does not proceed to the next operation but a classification of the portion of the image as a background is performed.
This approach is not suitable for inexpensive and/or low-speed processors mainly used in consumer electronics because all areas of the image must be scanned, for example.